Seat core material
A seat core material of the present invention is a seat core material for vehicle including a thermoplastic resin expanded bead article and a frame member embedded in a peripheral edge portion of the expanded bead article. The frame member includes a front frame part, a rear frame part, and two side frame parts interconnecting the front frame part and the rear frame part. Slits crossing the two side frame parts are formed along a longitudinal direction with continuous parts left intact outside the side frame parts on both ends of the expanded bead article. The slit penetrates or does not penetrate the expanded bead article in a thickness direction. The continuous parts are formed in a curved shape or a bent shape.
1. A seat core material for vehicle comprising: a thermoplastic resin expanded bead article and a frame member embedded in a peripheral edge portion of the expanded bead article, wherein
the frame member includes a front frame part, a rear frame part, and two side frame parts interconnecting the front frame part and the rear frame part,
a first slit crossing the two side frame parts is formed along a longitudinal direction of the expanded bead article with continuous parts of the expanded bead article left intact outside the side frame parts on both left and right end portions of the expanded bead article,
the first slit at least partially penetrates the expanded bead article in a thickness direction,
the continuous parts are formed in a curved shape or a bent shape along a peripheral edge of the expanded bead article as viewed from the top,
the expanded bead article has a peripheral edge shape that narrows in a vehicle-width direction at increasingly rearward positions on a rear side of the expanded bead article, and
auxiliary slits are formed at least partially penetrating the expanded bead article in the thickness direction, respectively, in the expanded bead article outside the side frame parts forward from the longitudinal outer end portions of the first slit, wherein the auxiliary slits intersect the first slit in the front-back direction extend adjacent and follow the increasingly rearward positions in a contour that forms the narrowed shape at the width-wise outer end portions of the first slit and at least in part form the left and right end portions of the expanded bead article in the bent or curved shape.
2. The seat core material according to claim 1 , wherein the expanded bead article has an auxiliary slit penetrating or not penetrating in the thickness direction outside the side frame parts forward from longitudinal end portions of the slit.
3. The seat core material according to claim 1 , wherein a ratio of opening area of the slit is 25% or less of a projection area of the expanded bead article in top view of the seat core material in a mounted state.
4. The seat core material according to claim 1 , wherein a non-penetrating part of the slit has an interconnecting part in which a bend or curved shape is repeatedly formed.
5. The seat core material according to claim 1 , wherein a front-back length of the slit is 10 to 40 mm.
6. The seat core material according to claim 1 , wherein a minimum thickness of each of the continuous parts is 10 to 50 mm, and a front-back length of each of the continuous parts is 50 to 200 mm.
7. The seat core material according to claim 1 , wherein the slit has a length of 100 mm or more from the outer end portion in the vehicle-width direction, and is formed continuously in the vehicle-width direction.
8. The seat core material according to claim 1 , wherein each of the continuous parts is formed at a portion of 60 to 80% from the front end portion of the expanded bead article with respect to a front-back length of the center portion of the expanded bead article.
9. The seat core material according to claim 1 , wherein each of the continuous parts is formed at a part where is from the front-back center portion of the expanded bead article to the rear frame part.
10. The seat core material according to claim 1 , wherein a thickness Tf of a front end portion of the seat core material and a thickness Tr of a rear end portion of the seat core material are in the relationship Tr×1.5<Tf.